U.S. Pat. No. 4,112,984 discloses a funnel for attachment to a fuel tank engine-operated equipment. The funnel is provided with a cap, in turn having an air intake opening with an air filter. The funnel is thus always accessible for filling the tank.
U.S. Pat. No. 4,896,746 discloses a storage funnel designed for the retention of oil or a gasoline mixture for dispensing into an engine or tank. It may also be used to store parts. The storage funnel consists of a housing, a cover, a filler neck, a cap, and a second outer cover. The housing includes a rotatable valve for dispensing the liquid mixture.
U.S. Pat. No. 5,074,343 discloses a filler unit for filing small tanks. The unit attaches an inlet to such a tank, and allows for filling the tank without any spillage. The unit includes a body, a funnel, and a displacer integral with the funnel.
U.S. Pat. No. 5,316,059 discloses an oil filler funnel cap for internal combustion engines that includes an enlarged funnel receptacle with a resilient sealing closure.
U.S. Pat. No. 6,830,085 discloses a fuel tank inlet extension that includes a threaded translucent cylinder attached, at one end thereof, to a fuel tank inlet. Once the tank is filled to capacity, and the fuel therein rises within the attached cylinder, the original cap from the fuel tank inlet is attached to the body.
US Publication No. 20070079898 discloses a funnel-shaped device that includes a threaded spout for threading the device onto a head cover of an engine. The device includes ribbing at its widest juncture to assist in gripping the device.